U.S. patent application number 12/446388 was filed with the patent office on 2010-02-25 for system and method for automatically processing and/or machining workpieces.
This patent application is currently assigned to ABB AG. Invention is credited to Martin Kohlmaier, Rainer Krappinger.
Application Number | 20100049352 12/446388 |
Document ID | / |
Family ID | 39027459 |
Filed Date | 2010-02-25 |
United States Patent
Application |
20100049352 |
Kind Code |
A1 |
Kohlmaier; Martin ; et
al. |
February 25, 2010 |
SYSTEM AND METHOD FOR AUTOMATICALLY PROCESSING AND/OR MACHINING
WORKPIECES
Abstract
A system for automated processing of workpieces comprises at
least one handling apparatus having at least one measuring
arrangement configured to record at least one controlled variable
and at least one regulatory device configured to interact with the
at least one measuring arrangement to optimize the processing using
the at least one control variable. The processing also includes
machining, and the at least one handling apparatus includes a
robot.
Inventors: |
Kohlmaier; Martin; (Medling,
AT) ; Krappinger; Rainer; (Kaltenleuitgeben,
AT) |
Correspondence
Address: |
DARBY & DARBY P.C.
P.O. BOX 770, Church Street Station
New York
NY
10008-0770
US
|
Assignee: |
ABB AG
VIENNA
AT
|
Family ID: |
39027459 |
Appl. No.: |
12/446388 |
Filed: |
October 18, 2007 |
PCT Filed: |
October 18, 2007 |
PCT NO: |
PCT/EP07/09042 |
371 Date: |
April 20, 2009 |
Current U.S.
Class: |
700/103 ;
700/253; 901/41; 901/50; 901/9 |
Current CPC
Class: |
B25J 9/1633
20130101 |
Class at
Publication: |
700/103 ;
700/253; 901/50; 901/41; 901/9 |
International
Class: |
B25J 9/12 20060101
B25J009/12; G05B 13/02 20060101 G05B013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 19, 2006 |
DE |
10 2006 049 956.5 |
Claims
1-48. (canceled)
49. A system for automated processing of workpieces comprising: at
least one handling apparatus having at least one measuring
arrangement configured to record at least one controlled variable;
and at least one regulatory device configured to interact with the
at least one measuring arrangement to optimize the processing using
the at least one controlled variable.
50. The system as recited in claim 49, wherein the processing
includes machining.
51. The system as recited in claim 49, wherein the at least one
handling apparatus includes a robot.
52. The system as recited in claim 49, wherein the at least one
regulatory device is configured to optimize the processing by
correcting a prescribed motion sequence including at least one of a
trajectory and a position of the handling apparatus.
53. The system as recited in claim 49, wherein the handling
apparatus includes a distal end configured to hold at least one of
a tool and a workpiece.
54. The system as recited in claim 52, wherein the at least one
measuring arrangement is configured to determine at least one of a
force, a moment, a force difference, and a moment difference,
wherein the at least one controlled variable includes the force,
and/or the moment, acting in at least on predeterminable direction
relative to the tool and/or workpiece.
55. The system as recited in claim 54, wherein the forces are at
least one of bearing forces and contact forces.
56. The system as recited in claim 52, further comprising at least
One control device configured to interact with the regulatory
device and is capable of receiving correction values corresponding
to the corrected prescribed motion sequence so as to implement the
prescribed motion sequence.
57. The system as recited in claim 56, further comprising a
communication interface configured to provide wired or wireless
communication and data interchange between at least one of the
regulatory device, the measuring arrangement, and the control
device.
58. The system as recited in claim 56, wherein the at least one
regulatory device interacts with the at least one control device
and the at least one measuring arrangement so as to regulate the
force.
59. A method for automated processing of workpieces comprising:
recording at least one controlled variable using at least one
measuring arrangement of a handling apparatus; and optimizing the
processing using the at least one controlled variable.
60. The method as recited in claim 59, wherein the optimizing
includes correcting a prescribed, motion sequence using the at
least one control variable by correction at least one of a
trajectory and a position of the handling apparatus.
61. The method as recited in claim 59, further comprising
determining at least one of a force, a moment, a force difference,
and a moment difference using at least one measuring arrangement,
wherein the controlled variable used includes the force and/or
moment acting in at least on predeterminable direction relative to
at least one of a tool and a workpiece.
62. The method as recited in claim 61, further comprising
ascertaining control correction values using recorded controlled
variable measured values, transmitting the control correction
values to a control device of the handling apparatus, performing
position or trajectory optimization, and implementing the position
or trajectory optimization.
63. The method as recited in claim 59, wherein the recording
includes qualitatively recording at least one of a force and a
moment acting in at least one freely prescribable direction or
along at least one axis relative to at least one of the tool and
the workpiece.
64. The method as recited in claim 62, further comprising
transmitting the recorded controlled measured values to the
regulatory device.
65. The method as recited in claim 63, further comprising
regulating the force and/or moment.
66. The method as recited in claim 59, further comprising providing
parameters and selecting a suitable reference value from a
predeterminable set of reference values, wherein the optimizing is
performed based on the reference value.
67. The method as recited in claim 66, wherein the parameters
include at least one of a position of the at least one tool, a
material nature of the workpiece, a type of the processing, and at
least one additive used.
68. The method as recited in claim 59, further comprising using six
possible degrees of rotational freedom of the handling
apparatus.
69. The method as recited in claim 59, wherein the at least one
measuring arrangement uses at least one of a piezoelectric sensor,
a force transducer, and a differential pressure gauge to measure
the force or moment.
70. The method as recited in claim 59, further comprising taking
into account at. least one of a complex shaping, a material, and a
material transition of the workpiece.
71. The method as recited in claim 59, further comprising recording
at least one of a physical variable and a process-related
variable.
72. The method as recited in claim 59, further comprising using an
additive.
73. The method as recited in claim 62, further comprising selecting
a type of trajectory optimization under program control using at
least one predeterminable characteristic Or at least one further
parameter.
74. The method as recited in claim 61, further comprising taking
one or more prescribable parameters as a basis to select a
respectively suitable reference value from a predeterminable set of
reference values.
75. The method as recited in claim 73, wherein the one or more
prescribable parameters include at least one of a current position
of at least one of the tool and the workpiece, a type of tool used,
and a type of the processing.
Description
[0001] This is a U.S. National Phase Application under 35 U.S.C.
.sctn.371 of International Application No. PCT/EP2007/009042, filed
on Oct. 18, 2007, which claims priority to German Application No.
DE 10 2006 049 956.5, filed on Oct. 19, 2006. The International
Application was published in German on Apr. 24, 2008 as WO
2008/046619 A1 under PCT Article 21(2).
[0002] The invention relates to a system and a method for the
automated machining and/or processing of workpieces, wherein at
least one handling apparatus, particularly a robot and/or an
industrially applicable robot, can be used to automatically perform
a prescribable machining and/or processing process for at least one
workpiece.
BACKGROUND
[0003] Robots are performing more and more tasks and functions as
part of industrial production. In this context, increased use is
being made of robots in order to position and/or assemble
components at a predetermined location, that is to say for assembly
purposes, but also increasingly for the purpose of machining
workpieces, such as for lacquering, grinding, laser-cutting,
polishing, drilling, milling, and the like, with appropriate robot
tools being equipped with the relevant machining tools, such as
welding heads, lacquering nozzles or laser-cutting apparatuses. In
this case, the robots perform preprogrammed movements with the axes
provided. To achieve at least uniform machining quality,
particularly for surface machining, it is necessary to stabilize
and/or inspect the contact forces between the workpiece to be
machined and the tool used for the machining. For this, industry
conventionally involves the use of different systems. When grinding
a workpiece, for example, compressed air can be used to apply a
predetermined contact pressure from the grinding tool to the
workpiece to be ground, in order to ensure continual contact
between the workpiece and the tool in the machining or production
process and to avoid a loss of contact and hence losses of or dips
in grinding quality. Other systems comprise mechanical suspension,
suspension by means of rubber blocks, electromagnetic suspension
with essentially comparable modes of operation and/or similar
operating principles, for example. Drawbacks have to date not
allowed known systems and/or methods to regulate and/or adjust the
applied contact forces with sufficient accuracy and/or speed,
particularly when using compressed air, which means that it has not
been possible to date to regulate a predeterminable or presettable
machining force or contact force to a constant value during the
machining process.
[0004] Particularly in the case of compressed air, this can be at
least proportionally attributed to the compressibility thereof,
since this means that it is not possible to ensure an airstream
which is constant in volume and speed. Further restrictions are
experienced by the known systems particularly also as a result of
physical laws in the process handling. Thus, when compressed air is
used, the achievable contact forces are limited by the performance
of the pressure supply (mains system and compressor). When
electrical systems are used, for example when electromagnets are
used, comparatively large currents and/or voltages are required in
order to overcome the existing resistances and generate the
necessary field strengths. The electromagnetic compatibility of the
other process components also plays a part in this context. In
addition, the contact forces which can be applied are also limited
by the physical shape, the design and the specific material
properties of the tools used and also of the workpieces to be
machined, and substantial differences can arise locally, for
example in a transition from a thick-walled to a thin-walled region
of the workpiece and/or when different materials are used with
different specific properties, such as surface hardness. With an
accordingly comparatively complex process structure, the
design-dependent flexibility of the handling appliances may also be
drastically restricted, and restricted compensation mechanisms may
result for the tools as a result of limitations on travel. This may
in turn result in automated systems being unable to compensate for
varying dimensional accuracy in the components. Further correction
or adjustment of the applied contact forces may also be required
when tool wear occurs, for example. Such automated adjustment has
also not been adequately possible to date using known systems and
methods, which means that the underlying machine processes can
often be implemented only manually, ultimately resulting in natural
deviations and/or differences in the machining arising and each
machined component being given the nature of a unique item.
SUMMARY OF THE INVENTION
[0005] Accordingly, an aspect of the present invention is to
provide an improved way of achieving a reproducible and/or uniform
machining quality during automated machining, particularly during
surface machining, of a workpiece, particularly also under varying
ambient conditions.
[0006] Advantageous embodiments and developments of the system
according to the invention and an appropriate method for machining
and/or processing workpieces are specified in the claims and in the
description which follows.
[0007] The inventive system for the automated machining and/or
processing of workpieces has at least one handling apparatus,
particularly a robot or industrial robot, having at least one
measuring arrangement for recording at least one controlled
variable, wherein at least one regulatory device is provided which
interacts with at least one measuring arrangement and takes account
of the at least one controlled variable for the purpose of
optimizing the respective machining and/or processing process.
[0008] In one advantageous embodiment of the system, the respective
machining and/or processing process is optimized by means of
controlled-variable-dependent correction of a prescribed motion
sequence and hence by correcting the trajectory and/or position of
the handling apparatus.
[0009] One development of the system provides for at least one
holding apparatus, arranged at a distal end of the handling
apparatus, for holding at least one tool or at least one
workpiece.
[0010] The at least one tool which may be used in this case is, in
particular, a grinding and/or polishing and/or milling and/or
deburring tool.
[0011] The at least one workpiece which may be used in this case
is, in particular, housing elements, for example camera housing
parts, to be polished and/or to be ground and/or to be deburred.
The housing elements may be formed from magnesium or aluminum or a
combination thereof, for example.
[0012] In one embodiment of the system, at least one measuring
arrangement is provided for the purpose of determining forces
and/or moments and/or for the purpose of determining force and/or
moment differences, wherein the controlled variable taken into
account and/or utilized is the forces and/or moments acting in at
least one predeterminable direction between the tool used and the
respective workpiece.
[0013] In one system development, at least one control device is
provided for the purpose of position and/or motion control of the
handling apparatus, said device interacting with the at least one
regulatory device such that the control device is sent control
correction values, particularly motion and/or position correction
values, corresponding to respectively performed position and/or
trajectory optimization, for a prescribed motion sequence and/or
trajectory profile for implementation.
[0014] The system may also have provision for the aforementioned
measuring arrangement to be able to absolutely record,
qualitatively, the forces and/or moments occurring or acting in at
least one freely prescribable direction and/or along at least one
axis between the tool and the workpiece and/or for the recorded
measured values to be able to be transmitted to the regulatory
component via at least one provideable interface for communication
and data interchange.
[0015] In a further embodiment of the system, it is advantageously
possible to provide for forces and/or moments, or force and/or
moment deviations, occurring along at least one axis and/or in at
least one prescribable direction to be recorded relative to at
least one predetermined value and/or transmitted to the regulatory
device via at least one provideable interface, particularly by
wire, such as by means of USB, Ethernet, RS-232, Fire-Wire, SCSI or
another LAN, or wirelessly, such as by means of Bluetooth,
infrared, a radio link or another WLAN for communication and data
interchange.
[0016] Advantageously, it is also possible to provide for the at
least one direction to be freely definable in the space of a static
and/or moving reference system or coordinate system, which allows
optimized trajectory correction and, as a result, optimum use of a
respective tool for machining the respective workpiece, even when
there are a multiplicity of machining processes and/or even when
the ambient parameters are variable.
[0017] In one advantageous embodiment of the system, the regulatory
device interprets and processes the transmitted measured values of
the respective controlled variable and/or, as a result, ascertains
a respective motion or trajectory correction and/or corresponding
trajectory correction value for the handling apparatus and/or
effects appropriate trajectory and/or position optimization.
[0018] In particular, the at least one regulatory device interacts
with the control device and the at least one measuring arrangement
so that the force acting in at least one predeterminable direction
and/or the moment acting in at least one direction is regulated to
and/or kept constant at at least one predetermined reference
value.
[0019] In one development of the system, the regulatory device is
used to select a respectively suitable reference value from a
predeterminable set of reference values, which are stored
particularly on a data store so as to be able to be called, on the
basis of one or more prescribable parameters, such as the current
position of the tool or the workpiece, the type of tool used, the
type of the respective machining or processing process.
[0020] Accordingly, provision may be made for the regulatory device
to have a data store with stored reference values.
[0021] In one advantageous development of the system, the measured
value recording and/or processing is effected cyclically or
continuously by the measuring arrangement in interaction with the
regulatory device, in which case the resultant trajectory and/or
position correction or trajectory and/or position optimization is
also effected cyclically or continuously.
[0022] Advantageously, the at least one handling apparatus is in
single- or multiple-axis form, particularly six-axis form, which
means that there are six possible degrees of rotation freedom.
[0023] In one advantageous development of the system, the at least
one regulatory device is integrated in the control device and is
part thereof.
[0024] In a further embodiment, the regulatory device is of modular
design and/or can be integrated into the control device.
[0025] In particular, the control device and/or regulatory device
and/or measuring arrangement have at least one respective interface
for wired and/or wireless communication and/or for data
interchange.
[0026] By way of example, these may be hardware interfaces between
physical systems, such as PCI-bus, SCSI, USB, Firewire or else
RS-232, and/or data interfaces for interprocess communication
(IPC), particularly over a network, such as Remote Procedure Call,
DCOM, RMI or CORBA, or else ODBC and JDBC. The known network
protocol such as TCP, HTTP, etc. can also be understood to be IPC
interfaces.
[0027] It is also advantageously possible to use the popular
industrial and/or field bus systems and their interfaces for data
interchange and/or data communication. These also include CAN-BUS,
Profibus, field bus, MOST-bus, LIN-bus, EIB, KNX or else FlexRay,
for example.
[0028] In another embodiment, the measuring arrangement comprises
at least one force and/or moment sensor based on one of the
principles/types cited below: [0029] piezoelectric sensor; in a
piezoelectric sensor, pressure, that is to say force per area, is
used to produce an electrical voltage in a crystal, with electrical
charges being isolated in the crystal (piezoelectric effect). In
this case, the electrical voltage changes in a predetermined range
in proportion to the force. This effect also works the other way
around, so that applying an electrical voltage to the piezoelectric
sensor causes the latter to deform. Furthermore, piezoelectric
sensors afford several advantages, for example they are insensitive
toward high temperatures, no external power supply is required and
their efficiency is comparatively high. [0030] force transducer;
when force transducers are used, action of force causes a spring
element to elastically deform, the force needing to be taken up in
a prescribed direction. The deformation of the spring body, usually
metal, which is brought about by the action of force is converted
into electrical voltage by means of expansion measuring strips. An
appropriately providable measurement amplifier, for example, is
then used to register the electrical voltage brought about by the
action of force and hence the expansion change, and/or said
electrical voltage and hence expansion change can be converted into
a force measured value on the basis of the elastic properties of
the spring body. [0031] differential pressure gauge; this measures
the difference between two absolute pressures, what is known as the
differential pressure. The differential pressure sensor may have
two measuring chambers which are hermetically isolated from one
another by a diaphragm. The measureable deflection in the diaphragm
is then a measure of the size of the differential pressure. The
chambers may be filled with liquid, particularly also with a gel of
appropriate viscosity.
[0032] In one advantageous embodiment, at least one measuring
arrangement for determining forces and/or moments or for
determining force and/or moment differences is arranged in the
region of at least one of the axes or axes of rotation of the
handling apparatus.
[0033] The system may also have provision for at least one
measuring arrangement to be in the form of part of the kinematics
of the handling apparatus.
[0034] In one development of the system, the handling apparatus is
in the form of a robot, particularly in the form of an industrially
applicable robot, with at least one axis of rotation, but
particularly six axes of rotation.
[0035] In one development of the system, the handling apparatus
moves the respective tool relative to the workpiece along a
predetermined trajectory.
[0036] Alternatively, provision may also be made for the handling
apparatus to move the respective workpiece relative to the tool
along a predetermined trajectory.
[0037] In addition, it is possible to provide for the measuring
arrangement to allow forces and/or moments to be determined or
force and/or moment differences to be determined in one or more
axes, particularly six axes, and/or a resultant comprising a
plurality of axes of the handling apparatus.
[0038] In one development of the system, the holding apparatus has
a grinding and/or polishing machine and/or a miller and/or a
deburring tool.
[0039] Advantageously, it is possible to provide for complex
shapings and/or material transitions and/or different materials of
the workpieces also to be taken into account or able to be taken
into account and/or able to be implemented in the regulatory
device.
[0040] In one advantageous embodiment of the system, further
measuring arrangements are provided for recording further physical
variables for the tool, workpiece and/or handling apparatus, for
example.
[0041] In particular, it is possible to provide for the regulatory
device to influence process variables indirectly and/or
directly.
[0042] In another form of the system, a multiplicity of measuring
arrangements of different form, function and design, such as force
sensors, pressure sensors, distance gauges, motion sensors, speed
sensors, position sensors, conductimeters, optical sensors and
sensing elements, particularly for temperature and/or humidity, are
used in interaction or separately from one another for recording
measured values and/or forming measurement signals.
[0043] In one advantageous embodiment, the regulatory device also
takes account of the use of additives supporting the respective
machining process, such as the use of different grinding pastes for
grinding and/or polishing, different granulations for grinding
and/or polishing and/or sandblasting, through suitable parameter
selection, wherein, by way of example, each additive has at least
one appropriate process parameter associated with it, for example a
specific reference value for the controlled variable, particularly
the contact force between the grinder and the workpiece, but also
the machining speed or speed of the handling apparatus, for
example.
[0044] In one development of the system, the recorded measured
values from the measuring arrangement are used for absolute or
relative calibration of the handling apparatus.
[0045] Advantageously, the system may also have provision for one
or more machining steps, including with different tools and/or
ambient conditions or parameters, to be possible, with provision
advantageously being able to be made for the change of tools and/or
parameters and/or the parameter-specific reference value adjustment
to be performed automatically.
[0046] In addition, it is advantageously possible to provide for
different orientations of the respective machining or processing
tool, for example requisite oblique application of the grinder to
the respective workpiece, which forms an angle between the normal
to the surface of the workpiece and the axis of rotation of the
grinder, to be able to be taken into account and/or to have no
influence on the manner of operation of the measuring arrangement
and/or the regulatory device.
[0047] In one advantageous embodiment of the system, the manner of
operation of the measuring arrangement and/or of the regulatory
device is independent of the relative motion and/or relative speed
between the tool and the workpiece.
[0048] Advantageously, the use of the measuring arrangement and/or
regulatory device and the optimization process does not adversely
affect the manner of operation and flexibility of the handling
apparatus and/or any supply lines.
[0049] By taking into account a measureable controlled variable,
the abovementioned system thus allows a reproducible and/or uniform
machining quality to be achieved, particularly during surface
machining, even with changing ambient parameters, for example
different grinding pastes and, as a result, different contact
forces during different grinding and/or polishing operations.
[0050] The present invention also provides an appropriate method
for the automated machining and/or processing of workpieces,
wherein at least one measuring arrangement of a handling apparatus
is used to record at least one controlled variable, and at least
one regulatory device is used to optimize the respective machining
and/or processing process by taking account of the at least one
controlled variable.
[0051] In one embodiment of the method, the respective machining
and/or processing process is optimized by taking the ascertained
controlled variable as a basis for correcting a prescribed,
particularly programmed, motion sequence and hence correcting the
trajectory and/or position of the handling apparatus.
[0052] The machining and/or processing processes applied in this
context are particularly grinding and/or polishing and/or milling
and/or deburring processes, and, on that basis, appropriate tools,
particularly grinding machines, polishing machines, millers and/or
deburrers, are also used.
[0053] In one development of the method, at least one measuring
arrangement is used to determine forces and/or moments and/or to
determine force and/or moment differences, wherein the controlled
variable taken into account is the forces and/or moments acting in
at least one predeterminable direction between the respective tool
used and the respective workpiece.
[0054] Advantageously, it is also possible to provide for the at
least one direction to be able to be defined freely in the space of
a static and/or a moving reference system or coordinate system,
which allows optimized trajectory correction and, as a result,
optimum use of a respective tool for machining the respective
workpiece, even when there are a multiplicity of different kinds of
machining processes and/or even when ambient conditions or
parameters are variable.
[0055] In a further embodiment of the method, the recorded
controlled-variable measured values are used to ascertain
appropriate control correction values, particularly motion and/or
position correction values, and to transmit them to a control
device for the handling apparatus in order to perform appropriate
position and/or trajectory optimization for implementation.
[0056] The method may also have provision for the aforementioned
measuring arrangement to absolutely record, in particular
qualitatively, the forces and/or moments occurring and/or acting in
at least one freely prescribable direction and/or along at least
one axis between the tool and the workpiece and/or to transmit the
recorded measured values to the regulatory device, for example via
at least one provideable interface for communication and data
interchange.
[0057] In another embodiment of the method, provision may
advantageously be made for forces and/or moments, or force and/or
moment deviations, occurring along at least one axis and/or in at
least one prescribable direction to be recorded relative to at
least one predetermined reference value and/or to be transmitted to
the regulatory device via at least one prescribable interface, in
particular by wire, for example by means of USB, Ethernet, RS-232,
Firewire, SCSI or another LAN, or wirelessly, for example by means
of Bluetooth, infrared, a radio link or another WLAN for
communication and for data interchange.
[0058] In one advantageous embodiment of the method, the at least
one regulatory device is used to interpret and process the
transmitted measured values of the respective controlled variable
and/or, as a result, to ascertain a respective motion or trajectory
correction and/or corresponding trajectory correction value for the
handling apparatus and/or to effect appropriate trajectory and/or
position optimization.
[0059] In particular, the force acting in at least one
predeterminable direction and/or the moment acting in at least one
direction is regulated to and/or kept constant at at least one
predetermined reference value.
[0060] In another embodiment of the method, one or more
prescribable parameters, such as the current position of the tool
or the workpiece, the type of tool used, the type of the respective
machining or processing process, is/are taken as a basis for
selecting a respectively suitable reference value from a
predeterminable set of reference values which can be stored
particularly on a data store so as to be able to be called.
[0061] In one advantageous development of the method, the measured
value recording and/or processing is performed cyclically or
continuously, in which case the resultant trajectory and/or
position correction or trajectory and/or position optimization is
also performed cyclically or continuously.
[0062] Advantageously, the method may have provision for, in
particular, six possible degrees of rotational freedom of the
handling apparatus to be taken into account.
[0063] In one advantageous development of the method, the
communication and/or the data interchange, particularly when the
recorded measured values and/or the position and/or trajectory
correction values are transmitted, can each be effected by wire or
wirelessly using suitable interfaces.
[0064] By way of example, these may be hardware interfaces between
physical systems, such as PCI-bus, SCSI, USB, Firewire or else
RS-232, and/or data interfaces for interprocess communication
(IPC), particularly over a network, such as Remote Procedure Call,
DCOM, RMI or CORBA, or else ODBC and JDBC. The known network
protocols such as TCP, HTTP, etc. can also be understood to be IPC
interfaces.
[0065] Popular industrial and/or field bus systems and their
interfaces can also advantageously be used for data interchange
and/or data communication. By way of example, these also include
CAN-BUS, Profibus, field bus, MOST-bus, LIN-bus, EIB, KNX or else
FlexRay.
[0066] In another embodiment, the method involves the use of at
least one piezoelectric sensor and/or a force transducer and/or a
differential pressure gauge as a force and/or moment sensor.
[0067] The method may also have provision for the at least one
handling apparatus to be used to move the respective processing or
machining tool relative to the workpiece along a predetermined, in
particular programmed, trajectory or alternatively to move the
respective workpiece relative to the tool along a predetermined, in
particular programmed trajectory.
[0068] In one variant embodiment, the measuring arrangement is used
to determine forces and/or moments or to determine force and/or
moment differences in one or more axes, particularly six axes,
and/or a resultant, comprising a plurality of axes, of the handling
apparatus.
[0069] It is advantageously possible to provide for complex
shapings and/or material transitions and/or different materials of
the workpieces also to be taken into account in line with the
method.
[0070] Provision may also be made for further physical and/or
process-related variables, particularly for the tool, workpiece
and/or handling apparatus, to be recorded.
[0071] In one variant embodiment, a plurality of measuring
arrangements of different form, function and/or design, for example
force sensors, pressure sensors, distance gauges, motion sensors,
speed sensors, position sensors, conductimeters, optical sensors
and sensing elements are used, particularly for temperature and/or
humidity, in interaction or separately from one another, for
recording one or more controlled variables and the respective
measured values and/or the resultant measurement signal.
[0072] In one advantageous form of the method, account is also
taken of use of the respective parameter selection, wherein, by way
of example, each additive supporting the machining process, such as
different grinding pastes for grinding and/or polishing, different
granulations for grinding and/or polishing and/or sandblasting, is
assigned at least one further process parameter, for example a
specific reference value for the respective controlled variable,
particularly the contact force between the grinder and the
workpiece, but also the machining speed or speed of the handling
apparatus, for example, on a characteristic-specific and/or
parameter-specific basis through suitable combination.
[0073] In one development of the method, the recorded measured
values from the measuring arrangement are also used for calibrating
the handling apparatus.
[0074] Advantageously, the method may also involve one or more
machining steps, including with different tools and/or under
different ambient conditions or parameters, being processed, it
being advantageously possible to provide for a change of tools
and/or a parameters and/or a parameter-specific reference value
adjustment to be performed automatically.
[0075] It is also advantageously possible to provide for different
orientations of the respective machining or processing tool, for
example requisite oblique application of the grinder to the
respective workpiece, which forms an angle between the normal to
the surface of the workpiece and the axis of rotation of the
grinder, to be able to be taken into account and/or to have no
influence on the method sequence or the performance of the
method.
[0076] In one variant embodiment, the type of trajectory
optimization, or the underlying process parameters, is/are selected
under program control using at least one predeterminable
characteristic.
[0077] One embodiment of the method also provides for one or more
prescribable characteristics, such as the current position of the
tool or the workpiece, the type of tool used, the type of the
respective machining or processing process, to be taken as a basis
for selecting a respectively suitable reference value from a
predeterminable set of reference values which may be stored on a
data store, in particular, so as to be able to be called.
[0078] It is also advantageously possible to provide for the at
least one workpiece to be processed or machined using at least one
single-axis or multiple-axis handling apparatus.
[0079] In another embodiment of the method, at least one
measurement signal or the force and/or moment measured values
recorded in at least one direction is/are output and/or forwarded
as absolute values.
[0080] The method may advantageously have provision for the motion
trajectory of the handling apparatus to be optimized in an
application-specific manner between two freely prescribable
positions on the basis of the measurement signal or the recorded
measured values.
[0081] In a further form of the method, the result of the
measurement or the evaluation and/or interpretation of the measured
values bring about a flexible change in the motion sequence or the
process sequence and/or the underlying program.
[0082] It is advantageously also possible to provide for
single-dimensional or multi-dimensional variables and/or measured
values and/or correction values to be ascertained.
[0083] Advantageously, the method can be used universally and/or
largely independently of the type and/or form and/or nature of the
respective workpiece and/or of the respective tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0084] The invention and advantageous embodiments are illustrated
further with reference to a FIGURE and exemplary embodiments.
[0085] FIG. 1 shows an example system design for the automated
machining and/or processing of workpieces.
DETAILED DESCRIPTION
[0086] FIG. 1 shows an example system design for the automated
machining and/or processing of workpieces. The handling apparatus 4
provided is a multiple-axis robot or industrial robot, particular a
six-axis robot, having at least one measuring arrangement 8 with at
least one force sensor for recording at least one controlled
variable 9.
[0087] The distal end of the robot 4 is provided with a holding
apparatus 12 for holding at least one tool 6, in the example shown
here a grinder or a grinding machine 6. For example, the holding
apparatus 12 may have a flange and/or gripper and/or changing
magazine for tools.
[0088] In principle, however, it is also possible to use further
processing tools, such as particularly a polishing and/or milling
and/or deburring tool and/or welders.
[0089] In addition, a regulatory device 10 is provided which
interacts with the measuring arrangement 8 and takes account of the
at least one controlled variable 9 to optimize the respective
machining and/or processing process by performing and/or prompting
controlled-variable-dependent correction of a prescribed motion
sequence and hence trajectory and/or position correction of the
robot 4 or of the tool 6 relative to the workpiece 2.
[0090] An example cited for a workpiece 2 is a housing element,
particularly a camera housing part, which needs polishing. The
housing elements may be formed from magnesium or aluminum or
plastic or a combination thereof, for example.
[0091] The measuring arrangement 8 for determining forces and/or
moments and/or for determining force and/or moment differences
records the bearing force and/or contact force acting in at least
one predeterminable direction R between the tool 6 used and the
respective workpiece 2 as a controlled variable 9.
[0092] In addition, a control device 14 having a display 16 and
input device 18 is provided for the purpose of position and/or
motion control for the robot 4 and interacts with the regulatory
device 10 such that the control device 14 is sent control
correction values, particularly motion and/or position correction
values, for a prescribed motion sequence and/or trajectory profile
which correspond to respectively performed position and/or
trajectory optimization and are implemented automatically by said
control device. In this case, these correction values are
proportioned such that a discrepancy between the respectively
recorded controlled-variable measured value and a predeterminable
reference value is compensated for, that is to say that the
respective controlled variable is regulated to a predeterminable
reference value.
[0093] In this case, it is possible to take parameters,
particularly to take the position of the tool and/or the respective
material nature of the workpiece and/or the respective machining
step and/or the additives used, for example various grinding and/or
polishing pastes, as a basis for using several different or
differing reference values too.
[0094] Advantageously, it is therefore also possible to perform
different machining steps and/or phases.
[0095] On the basis of the high level of automation and the
regulation of the bearing force between the tool and the workpiece,
a comparatively high level of machining and/or process quality,
particularly grinding and/or polishing quality, for the system and
for the method is reproducibly provided and achieved.
* * * * *